The present invention relates to an airbag module, and more particularly to an attachment arrangement, which supports the airbag module upon a plurality of switches while providing primary airbag module retention.
It is well known to provide an airbag module in a vehicle at such locations as in a steering wheel, a dashboard, a seat, door panel or other location. A typical airbag module includes an airbag inflator positioned adjacent an airbag to discharge an inflator gas to inflate the airbag upon sensing certain predetermined vehicle conditions.
The airbag module is commonly formed as a separate and independent unit from the vehicle. The airbag module must be easily installed yet difficult to remove by an unauthorized person. Attachment of the airbag module is further complicated by the requirement that a horn actuator be mounted to the steering wheel assembly. Typically, the horn is triggered by pressure applied to a portion of an airbag cover.
In one known arrangement, the airbag module is rigidly anchored to a base plate within a cavity formed by the molded armature of the steering wheel assembly. A thin film actuator to activate a vehicle horn is located between the airbag module and an airbag cover. Pressure applied to the airbag cover triggers the thin film actuator to selectively actuate the horn. However, mounting of the airbag module is typically with threaded fasteners, which may complicate assembly and disassembly. Further, as the thin film actuator is mounted below the airbag cover and above the airbag module, replacement of the actuator may be complicated and time intensive should the thin film actuator fail.
In another known arrangement, a switch assembly is mounted to a base plate within a cavity formed by the molded armature. The airbag module is then mounted to the switch assembly, such that pressure applied to the airbag module moves the entire module and triggers the switch to activate the horn. The switch assembly must be particularly robust to support the airbag module yet be able to restrain the airbag module during airbag actuation. Disadvantageously, the robust design of the switch assembly results in a complicated and expensive switch assembly. A driver must also apply a relatively large amount of pressure to move the airbag module and trigger the switch. This may be rather inconvenient.
Moreover, as the switch is located under the airbag module, enough clearance must be provided to allow movement of the airbag module relative to the molded armature. Commonly, this results in a noticeable separation line or gap between the airbag module and the steering wheel assembly. The separation line may be aesthetically displeasing and may allow foreign objects to find their way between the airbag module and the steering wheel assembly. The separation line may be further exaggerated by tolerance differences between the steering wheel assembly, airbag module and biasing member within the switch assembly.
Accordingly, it is desirable to provide an uncomplicated airbag mounting arrangement, which provides effective airbag module attachment. The attachment should also allow convenient horn activation with minimal pressure. It is further desirable to minimize the separation line between the airbag module and the steering wheel assembly to provide an aesthetically pleasing steering wheel assembly.